Continuously loaded conductor



A ril 26, 1932. w, FONmLLER 1,855,571

CONTINUOUSLY LOADED CONDUCTOR Filed April 26, 1928 //vv/v ran WILL/AM Fan/alum A rpm/v5 V Patented Apr. 26, 1932 UNITED STATES PATENT oFFlcE I WILLIAM FONDILLER, or YONKERS, NEw. YORK, ASSIGNOR T BELL TELEPHONE LABO- RATORIES,INCORPORATED, on NEW YORK, N. Y., A CORPORATIONQF NEW YORK coNTIN ousLY LOADED connuc'ron.

Application filed April. 26,

The present invention relates to improvements in continuously loaded conductors.

A general object of the invention is to improve the transmission characteristics of continuously loaded signaling conductors.

A specific object of the invention is to increase the stability 'ofthe inductance of continuously loadedsignaling conductors under the action of'large disturbing magnetizing forces.

A further object of the invention is to apply magnetic loading material to a conductor in such a fashion that eddy current losses in said loading material are substantially decreased.

A feature of the invention is a continuously loaded signalingconductor in which the inductance per unit of length may be easily adjusted by means of a suitable combination of thenumber and width of air gaps introduced into the magnetic circuit of the loading'material. g

In accordance with the invention these obj cots are attained, in a preferred embodiment, by using any known method of electrolytic plating for depositing a sheath of loading material 011 the conductor, but so treating the conductor before depositing the loading material that the loading material will be deposited in the form of discontinuous areas, such as a succession of rings or spirals of loading material separated from each other by air gaps, or preferably in the form of a continuous sheath having a numberof air gaps symmetrically spaced with respect to the circumference of the conductor. I

One method of practising the present invention will now be described and the operation explained in connection with the drawings, in which;

Fig. l is a side view of the apparatus and the cable during the treatment in accordance with the invention;

Fig. 2 is a top view of the cable and apparatus;

Fig. 3 is a view in elevation of the conductor having the loading material applied thereto;

Fig. 4 is a view in elevation of a portion of the conductor having the loading material applied in spirals by electrolytic deposition 1928. Serial no. 272,881.

with narrow spiral gaps in between the as shown in Fig.2; the'rolls are so adjusted that only the projections 11 come in contact with the copper conductor 11. Four tanks 15 contain viscous insulating varnish 17 which oozes through the bottom and is wiped ofi' by brushes 16. The irictionbetween the toothlike projections 14 of rolls 1 1 and the bristles of brushes 16is suificient to rotate the brushes during the rotation ofthe rolls and to cause the insulating varnish to adhere to the front surfaces offthe "projections.

Thus during the rotation-otthe four rolls eight rectangular symmetrically spaced is-- lands of insulating varnish are imprinted upon the copper conductor. In its upward motion the treated conductor is passed through a heated'zone whereby theinsulating varnish is dried; The conductor is then ready to be' passed into an electrolytic bath for the purposefof depositing any suitable type ofloading material upon it. The metal I or alloy will be deposited only upon the me tallic surfaces while the insulated surfaces 7 will not be plated. Instead of the rectangulaniormoi air gaps any otherfform of air gaps such as ring-like gaps or gaps havin'g the form of a continuous spiral may befeasily produced bythe methods .of

vention.

nvention the l the present in- Lee It may be desirable or necessary to heat treat the conductor after the platingopera tion is completed. This treatment may be conductor I produced =by. the methods Mde effected in the ordinary manner. The insu-- i lating varnish will be removed by combusconstituting air-gaps.

- osition.

Conductors treated and loaded in accordance with this invention find a field of application in multiplexing of lines (as by carrier frequency) and in compositing of lines (in simultaneous telephony and telegraphy) where it is very advantageous to have a high degree of magnetic stability both during and after the application of large disturbing 'magnetizing forces. A high magnetic stability avoids impedance irregularities caused by the effects of various magnetizing forces, a condition which from the standpoint of repeater operation is highly'undes'irable.

The subdivision of the loading material in accordance with the inventiontends to cause its magnetic and electrical properties to be improved by such subdivision; forex ample, the eddy current losses will be reduced and the inductance of the loaded conductor caused to vary less with changes in current flowing through the conductor. 7

y The methods 7 of the present invention also provide aneasy means to accurately control the inductance per unit of length of a cable, since the amount of loading material deposited may be easily changed from point to point alongthe conductor during the dep- For this purpose an inductance measuring instrument may be connected to the conductor during the electroplating operation, whereby the progress of the loading may be followed. 1

Although this invention has been described with reference to a particular process, applicant does not intend to be limited thereto. The objects of the invention may obviously be attained by loading the conductor mechanically instead of electrolytically, for instance, by longitudinally applying thereto strips of loading material by passing the con- 'ductor through rolls forming the loading material about it in the form of a cylindrical renvelope, or by serving the conductor with one or more layers of loading material in the form of. tape orwir'e, the loading material in both cases having provided therein nonmagnetic gaps in accordance with the pur- V poses and principles of the invention; Fig.

, ductor; conductor 30 has applied to it strips 5 shows such modified constructionof conor tapesof loading material 31, these tapes being provided with perforations or air-gaps v 32. The perforations in the tapes may be made by any suitable method, for example,

by punching before the tapes are applied to the conductor.

The term tape in the appended claims is intended to cover all equivalents of tape, such as strips of wire, for instance.

What is claimed is:

1. An electrical conductor loaded with magnetic material distributed thereon characterized in this, that the magnetic material consists of discrete strips having numerous openings in the strips which constitute airgaps. a y

2. An electrical conductor having electroplated thereon magnetic material in the form of apattern, the unplated portions separating the plated portions.

3. An electrical conductor having electromagnetic loading material electroplated thereon upon distributed portions constituting less than the whole surface of said con-. ductor.

l. A conductor in accordance with claim 3, characterized in this that the form or area of the plated portions is varied along the conductor in a mannerto cause desired variations in the inductance per unit length of the conductor.

5. An electrical conductor having applied to its surface electromagnetic material with non-magnetic gaps between the portions of electromagnetic ,material inthe form of a pattern, whereby lines of magneticforce extending circumferentially around at least certain portions of the conductor and at right angles to the axis thereof intersect non-magnetic gaps. V i

In witness whereof, I hereunto subscribe my name this 19th day of April, 1928.

YVILLIAM FONDILLER. 

